1. Field of the Invention
The invention relates to an optical disc record carrier for recording information under servo control based on spindle revolution control and address information recorded on wobbled grove(s), an apparatus for manufacturing such a record carrier, an apparatus for recording information on such a record carrier, and an apparatus for reading information recorded on such a record carrier.
2. Description of the Prior Art
Spindle revolution control information and address information is often recorded in advance on such a record carrier as is done for ATIP (Absolute Time In Pregroove) in CD-R (Compact Disc-Recordable) in order to enable information to be recorded in desired positions. Specifically, spiral or concentric groove(s) is (are) formed on the record carrier with the groove(s) wobbled (or periodically changed in position in a direction transverse to the groove) in response to the spindle revolution control information and the frequency-modulated address information.
If application data is recorded on the groove(s), the modulated address information obtained from the wobbling of the groove(s) is correctly read, which permits the application data to be recorded in desired sectors on desired tracks. However, if a land is scanned in recording application data on both the groove and land tracks trying to increase the capacity of the optical disc, a mixture of wobbling signals from the grooves adjacent to the land being scanned is obtained as the modulated address information. This makes it difficult to correctly read only the wobbling signal from a groove associated with the scanned land. Accordingly, application data can be hardly recorded in desired position.
One solution for this problem is disclosed as "Optical Disc Recording Medium and Optical Disc Drive" in Japanese unexamined patent publication No. 9-231580 (1997). In this recording medium, a revolution control signal is recorded as wobbling of the groove(s), while address information is recorded as prepits formed in positions corresponding to the boundary between adjacent groove and land in ID area which is part of the groove and land tracks. The prepits enable the address information to be correctly read out both when a groove adjacent to the prepits is scanned and when a land adjacent to the prepits is scanned.
However, in addition to the fact that the ID area occupies part of the tracks, the ID area has to be followed by another area in which a variable frequency oscillator is inserted in order to facilitate the synchronization of the PLL (phase-locked loop). This causes the capacity of resultant optical disc to become small.
Thus, the tracks need to be divided into address areas and data areas in order to record application data on both the groove and land tracks, which makes it difficult to raise the recording density.
It is therefore an object of the invention to provide an optical disc record carrier having spiral or concentric wobbled groove(s) that permits (permit) recording application data on both groove and land tracks without occupying any portion of the tracks.
It is another object of the invention to provide an apparatus for manufacturing such a record carrier, and an apparatus for recording application data on such a record carrier and/or for reading application data recorded on such a record carrier.